RIEFFER'S HUMMINGBIRD 441 



worked, I concluded she was sucking up some of the excess water. 

 And with these unfailing maternal ministrations, the unfledged birds 

 pulled through the ordeal. Then I began to understand something 

 of the secret of the wide distribution and great abundance of the 

 species. Their nesting habits appear very imperfect, for the nest 

 seems to sacrifice utility to beauty, and in a region where a large 

 proportion of the birds build some sort of covered nest to protect its 

 occupants from burning sun and beating rain, theirs is open to the 

 sky, and moreover is too small to accommodate the two nestlings 

 until they are ready to leave it. Their success as a species resides 

 rather in the inherent toughness of fiber of the nestlings, coupled 

 with the indefatigable attentions of the devoted mother. 



Before leaving the nest, the fledglings acquired the plumage of 

 the adults, although the colors were not so bright, and tufts of 

 brown down still adhere to the tips of the green feathers, giving 

 them a rather rough appearance. Two days before their departure 

 from the nest, when I attempted to touch them they would ruffle 

 up their feathers and attack a finger with their bills, which were 

 still considerably shorter than the adult's. The first bird flew off 

 as I was examining the nest, at an age of 21 days. The folded 

 wings spread and began to whir, in a moment it rose into the air, 

 and, uttering a low twitter as it went, flew away until it was lost 

 from sight among the bananas. The maiden flight showed power 

 and control. The second bird left two days later, aged 22 days. 

 The mother continued to feed them by regurgitation for a number 

 of days after their departure; but I am unable to state just how 

 long. 



The nestling period of these birds was perhaps a few days longer 

 than normal because of the untoward circumstances attending it. 

 In the case of another nest I watched in Panama, the nestlings took 

 flight at the ages of 19 and 20 days, respectively. From a nest near 

 Tela, Honduras, the nestlings departed at ages of 18 to 19 days, 

 respectively, while from a second nest both departed at the age of 

 19 days. 



Eieffer's hummingbird sits lightly on her nest, and a greater por- 

 tion of her body protudes above it than is the case with most other 

 birds. This is the outcome of the closeness with which she molds 

 it to the central portion of her body and then often continues to add 

 down to the interior after the eggs have been laid, further decreasing 

 the size of the cavity. The nestling, at the time of its departure, is 

 almost as large as the adult, and naturally the two are very much 

 crowded in the small nest. Before they depart the wall is always 

 more or less flared outward by the pressure of their bodies, while 

 one or the other is forced to an uncomfortable position on the rim. 

 Especially when the nest is softened by water during rainy periods, 



